The present invention relates to communications systems and, more particularly, to a method and apparatus for monitoring integrity of leased transmission facilities in communications systems.
One way that telecommunication service providers compete with one another in the marketplace is through service quality. Service providers take elaborate steps to ensure that their telecommunications equipment provides constant, uninterrupted service. When equipment fails, the communication network quickly engages other equipment to ensure that communication traffic continues to be routed to its destination. Telecommunications service providers often offer minimum outage guarantees in which they guarantee to respond to equipment failure by restoring service within a minimum period of time. The period does not allow for manual diagnostic and cure. For example, such guarantees may specify that equipment failures are diagnosed and cured within two minutes.
To meet such minimum guarantees, the telecommunication service provider may provide a diagnostic processor within its communication network to monitor the status of network components. The diagnostic processor maintains a communication link with each and every component in the system to perform its monitoring function. When errors occur, the diagnostic processor identifies the failing hardware and reconfigures the remainder of the operable hardware to circumvent the failed component. Ideally, in this manner, the diagnostic processor reroutes calls within the network to prevent lost data and restore service to customers. Within the network, certain network resources that previously may have been idle are activated to replace network resources that failed. Such a method is currently in use in the FASTAR(copyright) system operated by ATandT, the assignee of the present invention.
To reroute calls within the necessary time-frame, the diagnostic processor must know that the equipment that previously was idle is operating properly. Accordingly, the diagnostic processor extends its monitoring function to idle and active network components equally.
As the demand for telecommunications service has grown, more and more telecommunications service providers are leasing capacity from other service providers. The leased capacity may be used to carry communication traffic. Alternatively, however, the leased capacity is used as a backup; it is held in reserve and allocated for use when equipment failures cause other capacity to become unavailable.
Among service providers, leasing arrangements rarely obligate a lessor service provider to dedicate specific communication equipment within its network for the use of its lessee. Instead, the lessor service provider becomes obligated only to accept a predetermined amount of data from the lessee at a first point of interface (xe2x80x9cPOIxe2x80x9d) and route the data from the first to a second POI. The lessor service provider is left to its own discretion to determine how the calls shall be routed through its network. In practice, the lessor""s network establishes communication pathways between the POIs that are convoluted; they also change over time.
In a leased capacity configuration, the lessee""s diagnostic processor possesses no communication links with the equipment of the lessor""s network. Accordingly, in an emergency, the diagnostic processor cannot determine whether the communication path established by the lessor network is properly made or whether the lessor""s equipment is operating. Failures within the lessor network cannot be detected. Therefore, although leased capacity may serve as a backup resource, uncertainty as to its availability may cause the leasing network to default in its obligations to guarantee minimum outage times to its customers.
Leased capacity also suffers an additional disadvantage in that a proprietor of the leasing network may fail to provide the capacity that it is obligated to provide. In such a case, the lessor network may use the capacity for its own purposes even though the lessor is obligated to provide the capacity to the lessee. In such a case, no communication pathway is established between the POIs. If the lessee network routed data to the lessor network, the data would be lost.
Accordingly, there is a need in the art for a diagnostic tool in communication networks that confirms the integrity of communication pathways established in facilities leased from another communication network. Further, there is a need in the art for such a tool that confirms such pathways without direct communication with the equipment that establishes the pathways.
The disadvantages of the prior art are alleviated to a great degree by a method and apparatus that verifies the integrity of communications facilities leased from another network. The present invention monitors an idle signal that is routed to the lessor network at first point of interface and should be returned from the lessor network at a second point of interface. If the idle signal is not returned, it indicates a failure of integrity in the leased transmission facilities. If the idle signal is not returned, the type of signal that is returned may indicate a type of error that has occurred, such as equipment failure or allocation of the facility for a different purpose.